最先端研究セミナー

講演者：　山本　亘彦（大阪大学大学院生命機能研究科　細胞分子神経生物学　教授）

演題：　Plasticity of Neuronal Circuits in the Mammalian Brain

日時： 2022年4月13日（水）12:00-13:00

Abstract:

The most interesting aspect in neuronal wiring is plasticity. We previously demonstrated that neuronal activity increases thalamocortical axon branching in sensory cortex. Our investigation of the molecular mechanism further suggests that Netrin-4 and Bdnf contribute to activity-dependent branch formation. The next intriguing question is how neuronal activity is converted into the molecular signals. To address this issue, we have been investigating dynamics of activity-dependent transcription factors by a single molecule imaging technique. The result demonstrated that repetitive binding of CREB to specific genome locations takes place by increasing neuronal activity. On the other hand, neuronal connections are also known to remodel after the brain injury, which is also due to a plastic property of the nervous system. A good example is that contralateral corticomecencephalic projection emerges after unilateral cortical ablation. Our recent study indicates that after hemispherectomy glial cell-derived factors are expressed in the denervated mid brain and promote the ectopic contralateral projection. Here I will discuss the plasticity of neuronal circuit formation by introducing the above two distinct topics.  

References:

1. Uesaka N, Hayano Y, Yamada A, Yamamoto N (2007) Interplay between laminar specificity and activity-dependent mechanisms of thalamocortical axon branching. J Neurosci 27:5215-23.

2. Yamada A, Uesaka N, Hayano Y, Tabata, T, Kano M, Yamamoto N (2010) Role of pre- and postsynaptic activity in thalamocortical axon branching. Proc Natl Acad Sci U S A 107: 7562-7567.

3. Hayano Y, Sasaki K, Ohmura N, Takemoto M, Maeda Y, Yamashita T, Hata Y, Kitada K, Yamamoto N. (2014) Netrin-4 regulates thalamocortical axon branching in an activity-dependent fashion. Proc Natl Acad Sci U S A 111:15226-15331.

4. Kitagawa H, Sugo N, Morimatsu M, Arai Y, Yanagida T, Yamamoto N (2017) Activity-dependent dynamics of the transcription factor CREB in cortical neurons revealed by single-molecule imaging. J Neurosci 37:1-10.

5. Chang L, Masada M, Kojima M, Yamamoto N (2022) Involvement of denervated midbrain-derived factors in the formation of ectopic cortico-mesencephalic projection after hemispherectomy. J Neurosci 42: 749-761.  

担当分野：脳発生　嶋村（内線：6583）